Thank you so much - You reminded me that Lion came out!
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OdinulfJul 20 '11 at 13:44

3

I didn't down vote it, but it's a major system upgrade - you have to expect some downtime for maintenance.
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ThomasJul 20 '11 at 13:51

9

feh. I downvote your downvote. There's a difference between a bad question and a naive question.
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Joel Spolsky♦Jul 20 '11 at 13:56

5

I'm sure a lot of people are wondering how long it's going to take and how long their system will be unusable. Many OS upgrade processes allow the user to continue to use their system while they unpack and copy files, so the question is reasonable. I've rewritten the question a bit.
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Joel Spolsky♦Jul 20 '11 at 14:00

4

My flippant answer was "Till you hear it roar!" but it actually just plays some lame music.
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MarkJul 20 '11 at 15:17

12 Answers
12

It's a safe bet that most people are out of business for less than an hour. Of course, you'll probably be spending hours exploring all the new features, so you might want to count that against your system being unusable for "real work" due to "exploration and play".

Since you can't easily interrupt things and won't have use of the mac once the installer logs you out to start the upgrade, do give yourself a little window in case things run long.

Here are some ballpark numbers people are reporting for upgrades with real life amounts of data on their macs:

iMac / Mac Pro + SSD: 8 to 15 minutes

iMac / Mac Pro + HD: 12 to 20 minutes

Portables: 15 to 30 minutes

full drives / Air with HD: 30 to 45 minutes

Furthermore, you won't really know how long it will take if problems crop up moving thousands of tiny files or the process hangs. Then you will need to research what to do if trying again doesn't sort things out for you.

Even if your install should take 15 minutes, why risk it until the pressure is off?

The problem with any prediction is that there are four parts to the install:

common prep tasks (pre-download any updates - lion won't have many to pre download now since it's new)

a file system check of all your data (to avoid problems with bad files or bad file system structure)

the standard install (move the old, write the new - most macs capable of Lion will be within 50% of each other for this part)

upgrade script to crawl through all the your files and programs, upgrade things, and then delete the now un-needed files.

Parts 2 and 4 are where "slow installs" take the majority of your time.

Most people will be done in less than an hour - but you can't really know if your install will go long until you let it start. It matters little that other people had a good experience if your is going to be especially slow.

You can run a full file system check before starting to be sure your directories won't trap the installer in an infinite loop, but other than deleting things like un-needed apps and files that might need "migration", you can't speed up the parts of the process that depend on your pre-existing data.

Major upgrades touch files that may have lain dormant for years. Problems with unused code or incompatible extras come to light during an upgrade. It isn't meant to cause issues, just a "house of cards" is more likely to come down when you are re-plumbing the system.
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bmike♦Jul 20 '11 at 18:59

After downloading it, the upgrade from Snow Leopard to Lion has taken 15-20 minutes on average and I literally have to do nothing to facilitate it. I grab a coffee and the upgrade's done before my cup's empty.

I think you really are going to have to accept that your system will be unusable for a half hour or so while you upgrade.... and if you don't backup first, and there's a problem, it could be unusable for a lot longer than that!

I won't update my main work machine for a week or two yet, for this very reason.

On my 2010 iMac 21" it took about 90 minutes. In part this is because I have a lot of development tools on the system and it appears after having completed the upgrade that Lion rearranged and updated some of these tools (which is above and beyond the "typical" update).

Another thing is that I had XCode 4 installed in Snow Leopard, and now it complained that it won't run on Lion. However, the new XCode is now free again in the App Store, so I downloaded it again and it runs fine now.

New OS installs can have problems. OSX is not imune (though I'm going the guess most people will have a lot less trouble than XP -> Vista).

There's no advantage in running Lion. Well, Mission Control looks nifty, and the security will be great, and support for file versions will be a life saver for the muggles who don't use Git (or even dropbox), and autosave will even save hardcore Git user's bacon.

There's a new Python installation. Will that replace my interpreter? I doubt it, but a new install can take hours to recover from.